Here's a brief rundown of what happened. The service interruption actually started overseas in Europe, the Middle East and Africa on October 10. Blackberry attributed the failure to a "core switch failure" and said that its back-up was not functioning properly (incidentally, this was not a security failure and there was no hacking, but a hardware issue). The end result was a massive backlog of E-mails that were not sent during the switch failure. By yesterday, the issue had spread to American blackberry users as well. At a press conference yesterday, Research in Motion said that, in the end, all E-mails would be sent and not dropped. As of now, all E-mail should be working in America (though this is not the case in other parts of the world) and backlogged messages are in the process of being sent.
Of course, the timing is awful for Research in Motion, which has faced at least one network problem a year since 2007. The news comes in the wake of an announcement in June that RIM would layoff 2,000 people, a little more than 10% of its workforce. It also comes just before the debut of the iPhone 4S, which will be in stores on Friday. Blackberry's market share is also declining.